1. Field of the Invention
The present invention is allied to the printing industry and is directed to the folding of a relatively wide printed web at speeds equal to the speeds of printing presses. Printed webs may therefore be delivered directly from printing presses to the folding machines of this invention without any slow-up from the commencement of the printing to and through to the folded and finished book or booklet. The web folding machine employs cooperative rollers having working boxes on the outer cylindrical surfaces thereof with various devices in the working boxes to effect web gripping, web releasing, web cutting, etc. utilized in the folding operation. It is the purpose of the instant invention to effectively strip a web bight from the web gripping mechanism to ensure there will be no undesired hangups of the fast moving printed webs around the cooperative rollers.
2. Description of the Prior Art
Web bight gripping devices are shown and described in my prior U.S. Pat. Nos. 4,073,485 and 4,113,243. These prior devices employ rods with radial arms to effect an opening and a closing of the gripping devices. In the wider gripping devices for comparably wider printed webs the torque effect of the operating rods is such that it becomes more and more difficult to effect a uniform closing of the gripper throughout the wide web.
Positive uniform gripping of a wide web has now been accomplished in the device shown in my copending application, Ser. No. 202,599, filed Oct. 31, 1980, and entitled CAM OPERATED GRIPPERS FOR PRINTED WEBS. It is to this device of this copending application that the present bight stripper has been incorporated. The bight stripper is constructed to move with the movable jaw in an in and out movement relative to a stationary jaw. Further, with the same energizing force effecting operation of the movable jaw the bight stripper is also moved relatively to the movable jaw. The bight stripper is equal in level to the movable jaw when the jaw is closed, but the bight stripper raises substantially when the movable jaw is open to thereby positively lift the web bight from the grippers during the opening of the movable jaw.